The Independent reported Egyptologist Campbell Price saying the movement could be the result of an ancient curse:

“I noticed one day that it had turned around. I thought it was strange because it is in a case and I am the only one who has a key.

“I put it back but then the next day it had moved again. We set up a time-lapse video and, although the naked eye can’t see it, you can clearly see it rotate on the film. The statuette is something that used to go in the tomb along with the mummy.

“Mourners would lay offerings at its feet.

“In Ancient Egypt they believed that if the mummy is destroyed then the statuette can act as an alternative vessel for the spirit. Maybe that is what is causing the movement.”.

But there could be a more reasonable explanation. Manchester University physics professor Brian Cox told the museum differential friction could be at play here. This would mean the stone of the statue and the glass of the shelf cause a vibration that allows the figure to turn.

Price pointed out though that the statue has been on this glass since being in the museum’s care and they haven’t noticed it moving before. What’s more, he said “why would it go around in a perfect circle?”